Warp-knitting machine and method of operating the same



c. A. HEPP WARP-KNITTING MACHINE AND METHOD Sept. 5, 1950 OF OPERATING THE SAME 3 Sheets-Sheet 1 Filed June 11, 1947 INVENTOR'. Can-Zr: Q. NW

Sept. 5, 1950 c. A. HEPP 2,521,213

WARP-KNITTING MACHINE AND METHOD OF OPERATING THE SAME Filed June 11, 1947 3 Sheets-Sheet 2 INVENTOR Z {/5 I Combs any? mmmi kgg gzcwwfl ATTORNEYS INVENTOR. CMQOS Cb. H: mm Kpvwxtd 8&(Mb5/ AfiORNEmS,

3 Sheets-Sheet 3 C. A. HEPP WARP-KNITTING MACHINE AND METHOD OF OPERATING THE SAME Sept. 5, 1950 Filed June 11, 1947 Patented Sept. 5, 1950 WARP-KNITTING MACHINE AND METHOD OF OPERATING SAME Carlos A. Hepp, Palisade, N. 5., assignor to Alfred 'I-Iofmann 8; Company, West New York, N. .l'.,"a

corporation of New Jersey Application June 11, 1947, Serial No. "153,968

(01. cease) 21 Claims.

This invention is a novel warp-knitting machine, being of that well known class of knitting machine wherein a multiplicity of warp yarns are fed'from one or two more reels or beams and are therebeyond conducted through one or more banks of yarn guiding eyes for manipulation into warp-knitted fabric by cooperation of such yarn eyes with banks of needles, sinkers and other conventional knitting instruments. The present invention is applicable to the production of various types of warp-knitted fabric, such as tricot or ribbedfabric, single or double; and for illustrative purposes the invention is shown embodied in a .double tricot knitting machine.

Referring to the prior art, the nearest Warpknitting machines known to applicant are those shown in- ,certain patents granted to the same assignee as the present invention, particularly prior Patents No. 2,394,161, granted February 5, 1946, and No. 2,397,663, granted April 2, 19%.

The general object of the present invention is to improve substantially the means of mechanism, conventionally located in the upper part of the Warp-knitting machine, serving to feed or supply the many yarns or the sheets of yarns to the banks of knitting instruments located in the lower part of the machine, whereby the improvement hereof may function to afford efficient, correct and reliable control of the yarn movements and the feed thereof to the knitting point; and a further object is to secure such advantages by mechanisms and devices that are simple, convenient and durable.

More particularly, it is an object hereof to insure the feed or supply, in each of a succession of ,knittingcycles, and to the requisite and accurate extent, of yarn, as called for by the knitting cycle, from an overhead supply or reel, with flow of the numerous yarns, or yarn sheet, around a yarn conducting means conventionally in the form of ,a polished guide rod, or a set or plurality of such rods, one of which may be fixed in location, but ,at leastone of which is a bodily shiftable tension applying rod, of a responsive character, resiliently movable advancingly and retractingly along or in effective relation to the yarn path in adapting itsactionto the feedjof the sheet of yarns toward the knitting point, andthe reverseaction, as necessitated by the operations of the yarn guides or e s dia so ate nit instruments C a i y riabl ul a d lack.

An additional object of the invention is to afford vaninriproved control of each yarn reel or rotary beam, to be operated in predetermined manner, with variable speed, and preferably with internittent stoppages; the reel having means for braking its advancing rotation in each cycle to prevent overfeed, and optionally having also an intermittent :driving'means, such as that shown'in said prior patent, operable to start each rotary action or the reel thereby torelieve the sheet of yarns frornthe overstrain of overcoming by their pull the inertia of the heavy loaded reel; by these means thus providing continuous and responsive control ofthe feed of the bank of yarns in each of the successive cyclesof knitting action and in coordinationwith'the actions of the knitting instruments below, and in the improved manner to beherein disclosed.

In each cycle the conventional active or swingable guide rod for the yarn sheet is require'd to undergo shifting movements, first advancingly to supply or release yarn advancingly to the knitting point as required by the knitting movementsfand 20 later retractingly for return shift to take up and prevent the slackness of theyarns thatwould otherwise occur by the knitting action. his a special object of the present invention to afford yarn control means for each reel such that the issuing yarns pass in succession over a plurality of shiftable yarn guide rods, preferably two thereof, the yarn releasing and taking up functions in each cycle being apportioned between the respective guiderodS in a manner advantageously to subdivide the yarn feed control actions between the tandem guide rods, with cooperative results. Specifically the respective rods perform different operations and functions due to different arrangements, .one of the rods being under resilient and the second under positive control, the latter being moved in a predetermined manner to pro ide partly the required duty and function, while the first rod is under the non-positive infiuenceof .a

spring or resilient means by reason of which the residue of the yarn control action, after considering the componentithereof provided by the second or positively acting guide rod, is cared for in a resilient manner. By this means the first guide rod is always yieldable onwardly by the pull of the yarns for the necessaryadvance of the fyarns in each cycle, and is self returnable under'lits spring retraction to take up the yarn slack that would otherwise be produced. By this arrangement the duplex yarn control mechanism as a whole is irr proveddn that the resiliently controlled first yarn guide "rod is to ala'rg'e' eiite'nt relieved of its excessive duty and its extended shifting movements incurred in the mechanism of said p or patent, while at the same time retaining resi -en't influence, in both directions, through.

s) which the desirable predetermined tension upon the yarns may be maintained in a manner essential for the perfection of the knitting cycle, while retaining also the function of controlling the reel rotation as will be described.

Further objects and advantages of the present invention will be indicated in the hereinafter following description of an illustrative embodiment of the invention. To the attainment of the objects and advantages recited the invention consists in the novel warp-knitting machine and the novel features of method, operation, combination, arrangement and construction herein illustrated or described.

In the accompanying drawings, Fig. 1 is what may be designated a left end elevation, in the same sense as in said prior patent, of a warpknitting machine of the straight type, and of the double tricot kind, embodying the features of the present invention; it being noted that the characteristic yarn control mechanism, while indicated at both the front and rear sides of the machine, is disclosed only at the righthand side of Fig. 1, considered as the front side of the machine. It is to be understood that while Fig. 1 shows sufficient of the operating parts of the machine to explain the structure and operation of the invention, many other parts and details are omitted, but can be ascertained by reference to said prior patent.

Fig. 2 is a left hand elevation of a portion of Fig, 1, and may be considered as being a sectional view taken on a fore-and-aft vertical plane somewhat beyond the left end of the machine, thereby better to show certain parts not clearly appearing in Fig. 1, and at the same time showing such parts applied symmetrically to the control mechanisms at both the front and rear sides of the machine.

Fig. 3 is a partial left end elevation of certain parts seen in Figs. 1 and 2, but in a considerably modified second form, within the principles of the invention.

Fig. 4 is an illustrative yarn motion diagram showing in two cycles the approximate character of the downwardly advancing or yarn supplying movements and the upwardly retracting or take-up movements of the lengths of the yarns which extend beyond the guide rod system on their way to the knitting point, the downward yarn advancing including specifically a resilient yield, and the upward retraction thereof constituting a esilient return, preventing slack and maintaining the necessary tension on the yarns fed from the reel to the knitting point; said diagram being drawn to show in principle only the total or resultant yarn feeding movements as described.

Fig. 5 is a left end elevation showing a further or third form or embodiment of the invention preferable for certain purposes over the first and second forms.

Fig. 6 is a motion diagram of one cycle showing not only the resultant motion or curve, as in Fig. 4, but also certain component actions derived through the method and means to be described.

Fig. 7 is a diagram illustrating one of many variations of yarn control and motion, with component and resultant curves, available under the principles of the present invention.

Fig. 8 is a contour view of a modified control device or cam, differing from that shown in Fig, 5, and affording a positive controlled coml ponent differing from those illustrated in the diagrams of Figs. 6 and '7. The two guide rod controls and resulting diagrams may be of great variety according to the warp knittin system followed, the tightness of the fabric et cetera.

The yarns and certain illustrated parts correspond generally with those illustrated in said prior Patent 2,394,161. Thus the opposite sheets of warp threads or yarns y are seen in Figs. 1 and 2 as extending downwardly from the front and rear supplies to where they pass through yarn guides or eyes 11 there being front and rear banks of such eyes mounted on a yarn guide carrier bar Y which in turn is mounted to sWing frontwardly and rearwardly and to move endwise for cooperation of the eyes with the other knitting instruments, including at each side banks of needles and sinkers, a presser plate and other conventional instruments.

The machine is of the tall upright type, accommodating the yarn supplies at a high elevation and permittin general downward travel or advance of the yarns to a low central knitting point, yarns from both reels being interknit in the double tricot fabric. The machine may be of extended length to accommodate several thousand warp yarns in each sheet. The heavy central frame may comprise lower frame uprights 9, with elevated cross frames ID on top of intermediate cross frames I2 supported by the lower frame members 9, these frame elements being interconnected by heavy longitudinals, not shown.

Somewhat above the knitting point is shown a centrally arranged rockaxle or shaft I3, rocked by an arm I3X, this carrying a drop bracket M at the lower portion of which are mounted the yarn guide eyes 1 which, with their carrier bar Y, are to receive conventional frontward, rearward and longitudinal knitting motions. The transverse swing of the drop parts i4 and Y is indicated on Fig. 1 by the central radius :1: thereof and the front radius .12 and rear radius x between which extreme radii the frontward and rearward oscillations of the yarn eyes y occur. At a lower point in the machine is a power shaft 55 which may be the cyclic main cam shaft, not shown excepting that in Fig. 5 it may be the constantly turning cam shaft l5.

Well above the cross frames [2 and supported by the upper frames H! are the front and back longitudinal reel shafts 16, each of which carries one of the yarn reels, comprising central cores I! with end flanges [8 between which the body of the wound yarns is confined. Each reel shaft, front and back, turns in end bearings, not shown, on the upper cross frame It], where the shaft is confined against endwise movement by shaft collars such as the left end collar 2|.

Each reel shaft I6 carries a gear 26 through which the reel is braked (or driven) enclosed within a housing 21; and this gear 26 is shown as meshed with a pinion 4| fast on a hollow shaft or sleeve 40. The reel may be variably braked by retarding the sleeve under control; or it may be driven from an interior driving shaft 15 acting through said sleeve and pinion as described in said Patent No. 2,394,161.

The reel braking means may follow the disclosure of said prior patent. On the sleeve shaft 40 is secured a brake drum 43, constituting a surface turning in unison with the reel, and engaged by friction means shown as a pair of back and front friction shoes 46 mounted by pivots 69 on back and front levers 41 and 48. The drum,

,5 while :turning in unison with the reel, 'is not on thereelshait lfi buton the parallel sleeveshaft MI. .Between each shoe and its lever may be cushioning means like the equalizing springs of 'theprior Patent N0.-Z,394=',161. The shoelever hubsfil'are fulcrumed on studs52, and. confined by a bridge piece 53. The hubs may carry mutuall-yimeshing sector gears 5i) operating .toequalize the swinging motions of the levers. The

shoes are spring-pressed against thedrum through an-adjustable-cross-spring 54, of predetermined highstrength, extending fromlever to lever. The spreading-or pressing apart of the shoe levers to relax the braking effect is performed througha shipper device IZllofdifferent formand action from thatdisclosed in theprior patent, as will'be further described.

Whereas in said prior patent the yarns from the reel pass around a fixed inner rod, which has no function other-than to guide, andethence outwardly and around a single shiftable guiderod, which is under resilient control, with the present improvement the yarn from the reel passes around two- (or more) separate shiftable 'guiderods in succession, under independentcontrols, and a fixed guiderod is unnecessary, but may be added according tothe arrangement used.

Thus, as seen in Figs. 1 and 2, each yarn 1 passes downwardly from its reel and around'a fixed position guiderod ifdesirable, andthence around-and under a first shiftable guiderod I96 carried upon a pair of swinging arms lfll', which arms are attached fast upon a rockaxle 168, through which one ofthe two controls is afforded, in this instance the resilient control.

From the swingable first guiderod 06 the yarn passes over and around asecond shiftableguiderod l-lii mounted upon the ends of a pair=ofcarrying arms Hi, which in this instance-are not fast but are loose upon a suitable fulcrum, as the same rockaxle 1'08, so-that the guide rod IIEI may be under an independent control, inthis in stance positive.

Following the terms used-in said-prior patent, the shiftable yarn-sheet conducting rods I66 and Hi] and the fixed rod [04A are herein termed yarn guiderods, or-yarn rods, being distinct from the yarn guides or eyes 1 each ofwhich at the knitting point handles but 'a single yarn. The spring-controlled yarn sheet conductor or rod lllfi'speciiically is-considered a tension rod, resilient rod or floating rod, and in viewof one function constitutes a brake-control rod. The other pre-timed or cam controlled rod H0 is specifically a non-tensioning rod, a positive rod or a yarnmotion follower rod.

As an illustrative arrangement, in Figs. 1 and 2, the first or resiliently controlled'guiderod or rather its arms liil extend inwardly from the rockaxle I08, while the arms ll! of the other or secondguiderod extend outwardly or frontwardly therefrom; but the arrangement of the guiderods and thei swingable arms may be greatly varied. For instance, in the second form of the invention as indicated in Fig. 3, both of the-shiftablerods and arms extend frontwardly or--outwardly, swinging for'convenience about thes-ame axis. Thisillustrates also theyarns passing preliminarily around a fixed guiderod [04A, and this may conveniently be-used as the axle for. the first andsecond shiftable rods [06A and IDA-carried on arms IOTA and HIA. The yarns thus pass downwardly below the fixed rod HMA and frontwardly and under the first shiftable rod 106A,

resiliently controlled, thence upwardly andcver shift, and vice versa.

the second shiftable :rod 1 IDA and thence downwardly to theknitting-point. The effective action is the same inprincipleas that to be-described upon thefirst form of Figs. :1 and 2. Mechanically, thearms PHAshould be loose on the fulcrum axle 1134A; while the arms 401A shouldbe connected so-as-to swing the rockarm 33 which is resiliently supported by the upright tension- -ing:spring34, this result being effectedeither by attaching both of said elements -33-and [01A to the axle [MA as a rockaxle orto a-common hub,

so that these partsare operated in substantially the same manner as the corresponding parts 33, 34 and 101 iniFigs. 1 and 2.

The rockarms for the two rods 106 and H9 may extend frontwardly or rearwardly-and swing about the same or difierent axes, and the yarn provided by the short rotation of thereelin-each cycle.

Describing first onFigs. 1 and 2 (the principles applying generally also to Figs. 3 and '5) the positive or predetermined shiftingmovements of thesecond guid -rod M9, .by which a-positive or predetermined yarn movement control is provided, without resilient yield, the carrying arms iii are shown as formed with one'or more pinand-slot adjustable connections H2 between at least one of the arms and along drop link H3, whose up anddown-movements cause the swing of the guiderod l ill. At the-foot-of-the link H3 is power means, such as a cam or acrank, adapted to efiect the desired positive movements with cyclical repetition.

In this embodiment the transverse swinging movements of the drop bracket is and-yarn guide carrier bar Y about their rocksha'ftlB are'taken advantage of to deliver the predetermined shiiting movements to the guiderods lit! at both the front and back of the machine. To'carry out this plan the lower end of the link H3 215 6011- nected tea-timed actuator ll i in'the nature-oi an eccentric or crank projecting from a collar H5 which is attached by screw i it to the rockshaft I3 from which the bracket M depends. By this arrangement, when thebracket and yarn eyes swing rearwardly, that is,leitward-to radial position {v in Figs. 1- and 2, and it becomes necessary at the front side to'provide or-release more yarn for the momentary purposes of the knitting cycle, this-result is accomplished by the swinging downwardly of the guiderod HG, through the action of the link H3. In this waythe positive or predetermined control action through the link M3 to the guiderod H8 is caused tocorrespond approximately or generally withthe'needs' of the knitting cycle. Exactitude is not necessary in the partial supplying of demanded yarn by'the pretimed lowering of the positivesecond rodtl ii; so long as it substantially relieves the first or tension rod of all extreme movement; and-the same with the partial taking up of slack. The Fig. 5 mechanism to be described is preferredin that it'uses a cam its designed for more-nearly correct action than the crank lh'lof Figs. ltc 3; affords.

, Thus, by the present invention the second yarn guide rod I I9 is positively controlled in th manner described, while the other or first guide rod Iilt acts under resilient control, taking care of the necessary residual yarn movements between supply and knitting point, the resilience being provided by the conventional tensioning spring 34 constructed and arranged similarly to the corresponding spring in said prior patent but providing, in cooperation with the second guide rod and its control, the new and advantageous mode of combination action and result of the present invention.

The resilient control of the first shiftable guide rod I66, at each side, is effected as follows. The rod supporting arms It? are fast on the rockshaft Hi8, extending inwardly therefrom, and

there is also fast upon the same rockshaft another rockarm 33, projecting frontwardly from th rockshaft and having an apertured end which cooperates with the upright tension spring 34, at the top of which is an apertured head 35 pressing upwardly upon the rockarm 33. Inside of the spring is an upright rod 3% which extends upwardly and loosely through the head 35 and thence loosel through the aperture in the rockarm end 33, so that the spring, bearing upwardly on these parts, may be expanded and contracted while the rod slides relatively downwardly and upwardly through the apertured parts 35 and 33. The rod 35 constitutes a guiding core for the spring while maintaining alignment of the described parts, and the lower end of the rod is threaded to carry a pair of lock nuts 31, readily adjustable upwardly and downwardly on the rod to predetermine the normal length and the compression of the spring and its yarn tensioning action. At its bottom end the rod 36 is connected with a stud 39 mounted on a lower frame part 9. The operation of these parts 33 to 38 is practically the same as the operation of the corresponding parts shown in the prior patent.

The first shiftable guide rod 66 at each side, being the guide rod which is resiliently supported by the long tensionin sprin 34, is herein utilized to control the reel braking means, and the reel driving means if any, as follows. The carrying arms iil'i of the resiliently supported rod I98 are mounted fast upon the rockaxle H38, and that rockaxle at its left end extends well beyond the yarn reel and upstanding frame parts to where it carries the frontwardly projectin rockarm 33 through which the force of the spring 34% is communicated to the rockaxle and to the tension rod I06. In this instance the rockaxle I08 extends further outwardly to the left, where it carries a shipper device I20, quite different in structure from the shipper device 95 of the prior patent, but having the same general function of controlling the braking or driving of the reel by means of spreading and releasing actions against the swinging extremities of the friction shoe levers. The shipper device I23 is a rocker taking the form of a double cam plate, fast on the rockshaft I08 and having opposite cam surfaces E2I which cooperate with contacts or cam rollers 49, in this instance at the free lower ends of the brake controlling shoe levers and 48. Fig. 1 shows the rocking cam plate I28 with its front and back cam surfaces or edges IZI functioning to control the braking of the reel, and indicates also another rocker cam l2? with similar but reversed cam surfaces, adapted to operate through suitable mechanism, including shoe levers, which, as shown in said prior patent, control the action of driving the reel in each cycle, as disclosed and explained in said prior patent. The use of an opposed pair of shoes and levers is preferred as giving balance and permitting the single floating spring 54 to operate both; but by anchoring the center of the spring, or arranging it otherwise, either lever-borne shoe serves the purpose Without need of the other. By applying a shipper directly to each shoe lever the spring could be omitted.

The braking control action of the parts thus described may be explained further as follows. At one point in each knitting cycle, as will be explained further on the Fig. 4 diagram, the drop bracket I4 and carried yarn eyes swing rearwardly, toward radius and this motion taken with the motions of other knitting instruments causes an excessive demand for yarn. At this point in the cycle, the rockshaft I3 turning slightly clockwise in Figs. 1, 2 and 3 causes at the same time the downward retraction of the front actuator or crank Ild on the rockshaft, giving thus a positive pull upon the link II3 and a lowering of the second shiftable guide rod Hi]. This, but only to a partial extent, serves to supply additional yarn toward the knitting point, but yet leaving a demand for further yarn and as well the need for a resilient action in the yarn control; these demands being supplied by the first or resiliently positioned floating guide rod I96. At the peak in the cycle when th extensive demand for yarn occurs, the yarn stretch between the knitting point and the positively controlled guide rod IIU must travel downwardly. The predetermined or positive lowering of the second rod I I!) at this moment partly answers the demand, while the balance of the demand for yarn is answered by the yielding movement of the first rod I06. Assuming that the reel is under forcible braking action when this part of the cycle commences, the first rod will be caused to yield, in this instance upwardly, by the enhanced tension upon the yarn stretches between the first and second rods and between the first rod and the reel. The yield of the first rod 906 being thus upwardly, looking at Figs. 1 and 2, rockaxle I08 that carries the supporting arms of the rod is caused to rock or turn clockwise. At this part of the cycle, as already explained, it is desirable that the braking action upon the reel be relaxed (and the drivin action, if any, enhanced), thus facilitating the rotating of the reel to supply permanently the length of yarn needed for the current cycle. This relaxing of the braking action is effected by the clockwise rocking of the axle I08. The action is as follows. The shipper cam I20, fast on the axle H18, must rock clockwise with the axle. The cam surface I2I at the inner side of the cam I20 is at a slant which provides an increasing radius With clockwise rocking movement, and the same is true of the surface at the outer side of the cam. This rocking movement therefore, produced by the arn pull acting through the first rod I06, causes the two cam surfaces to press against the cam followers or rollers 49 at the lower ends of the shoe levers 41 and 48. The shipper or rocking cam thus increases the separation or causes the spreading apart of the two shoe levers. This in turn substantially relaxes the braking effect of the shoes 46 upon the drum 43, and since the drum is connected by sleeve 4E and pinion M with the gear 26 on the reel shaft I6, the reel becomes re leased to a substantial extent from the braking action so that it is readily started into advancing' or counter-clockwise. rotation, supplyingthe demandedyarn. The spreading apart of the shoelevers-by the shipper cam need not be to a great extent, nor sufficiently to retract the shoes from the drum and indeed, asexplained in said prior patent, the. cushioning connectionsbetween the levers and the drumare such that contact is not broken although the friction and braking effect are substantially reduced. Subsequently, when the knitting instruments and bracket M approach the other extreme of their movements, tending to cause a substantial slackness in the supplied yarn, this slackness immediately allows the restoration of the first shiftable rod H36 under its-resilient control by the thrusting action of the tension spring 34 so that the rockaxie ltd returnscounterclockwise and the shipper device reverses its position, releasingv the shoe levers from. the thrustofthe shipper and permitting the cross spring 54 to drawforcibl toward each other the levers and thereby gradually increase the'braking action, causing stoppage of reel rctation, preventing overrunning by momentum, and ceasing the advancing feed of yarn'until-the cycle, going through several'phases of action in accordance with the particular typ of knitting in hand, arrives back at the point where there will be a repetition of the yarn control actions by the resiliently controlled floating rod 38' co operating with the positively controlled rod HQ.

As alreadyindicated,andshownby the heavyline resultant on theyarn motion diagram of Fig. 4- and the more completediagram of Fig. 6, the knitting cycle may-be fairly complicated as regards the demand for and the giving up or release of yarn by the knitting means; This depends uponthe-type of fabric and the specific knitting cycle, and may involve asmany as three, or even more, low points of peak or maximum demand,

and the same number of high points of maximum release or slack of yarn, as indicated by the total cycle a, b, c, d, e, f, g, h, j, la, La. This illustrative cycle is merely representative of the various cyclesthat maybe practiced and is shown without attempt at exactness, but rather in idealized form, suitable toexemplify the principles of the invention. Fig. 6 shows not only the basic diagram curve of yarn motionas stated, but also itsdissection to indicate an illustrative way of apportioning the total between the two component motions provided by the use of the independently controlled two guide-rods I and lit.

Fig. 5 shows somewhat diagrammatically the modification of the mechanism of Figs. 1 and 2' wherein the operation of the second or positively controlled rod H6 is effected; not from'the rock-- shaft is from which knitting instruments are actuated, but from an independent positive source of motion, commencing with a cam which can thereforebe contoured to deliver to the link H3 and the second rod llllmore truly the peer tive motions which may be best adapted to rclieve'the resilientl controlled or floating rod lot of the extreme actions or burdens hcretoforeimposed thereon.

The upper parts of Fig; 5' correspond with Figs. 1 and 2, bearing the same reference numbers down to the connecting link H3. This link in Fig. 5connects with the short of a rock lever 12% which. is pivoted at any convenientpoint, for example loosely upon the rocks l3 Thelink Hills-pivoted at liltl-to-the effective short arm of the rocklever, while the effective lon arm- I26 thereof has a pivotal connection withianother link extending from the controlling cam. To permit adjustment the long arm i23- is formed with a slot l2 and-this is engaged by a pin I28 at the upper end of anadjustable link I29 the lower end of which is. pivoted to the effective short arm of another rocklever lttv fulcrumed atl3l, with a spring I32 pulling the lever downwardly,. the effective long arm I33- carrying aroller l3dwhich restsupon the periphery of an operating cam 35 fast upon a constantly turning shaft such. as the main camshaft-l5.

The positive means or cam i35 forgiving predeterminedadvances and retractions of the second guide rod ll it in: each cycle maybe laid out by calculation andtest so as to afiord the optimum or ideal actuation of the rod Ht asapproximately represented by the thin one of the component curves of. the Fig. 6 diagram.

As thus far explained the present invention may be summed'up as follows. Each rotating reel advances to suppl yarn in each cyc1e,-with a brake means. to retard methodically each ad- Vance by means of a friction shoe bearing upon av surface or drum 3 rotatable on the sleeve shaft to and therefore in unison with the reel, and with a movable shipper means. I261 op,- erably connected to the shoe, as by. a lever and spring, to impose or relax variably the braking. of the reel. With theseknown elements is combined. a plural set ofshiftable yarn guiderods I061. l'lll' around which. in sequence the yarn feed'flows advancingly'toward the knitting point, each rod being displaceable in an advancing direction and returnable by retraction to provide the supplying and taking up of the yarn. The first of these shiftable rods me has resilient control'means including spring 3 3, rendering it dis-'- placeable and returnable in each cycle in response to variations of the pull and slack of the yarns flowin around it caused by variations in the knitting. demand for yarn. The second of these rods HE has control means for displacing and returning it independently'of the yarn'pull and slack; such means comprising a positive or power actuated mechanism 5 l2! l5 pretimedto supply. yarn to and take up yarn'from theknitting point in each cycle, namely, to a variable extent coordinatedwith but insufficient fully to satisfy the pull and slack, thus leaving a residual function. This function is provided bythe first rod,- resiliently controlled, which'has a mechanicalconnection I08 to the aforesaid shipper whereby, tothe extent that the yarn pull (or its slack) in any part ofv the cycle'exceeds' the supply (orthe take-up) afiorded by the predetermined'imsufficient or deficient advance (or the deficient retraction) of the second rod, the resilient yield of the first rod operates through the shipper to relax (or to impose) the braking of the reel thereby to facilitate (or to retard) the rotation of the reel to cause the feeding (or curtailing the feed) of yarn toward the knitting point at that part of the cycle.

This improvement may be statedm'ore broadly in the'aspect that insteadof applying the frictional brake means in a variable manner to retard'the reel, a similar result'is obtainable by the use of a braking or rotation-restraining means having a constant retarding action, but rendered variable in effect by a relative. action as between such rotation-restraining brake, of ample retarding effect, anda variable rotation-promoting means, or reel drive (which latter may include the knitting mechanism itself actingv through the variable pull of the yarns tending to advance the reel). The action of the shipper then will be, not to vary the friction braking action, but to cause the relative operation of such restraining means and promoting means, to deliver to the reel a preponderance of retarding or of advancing effect. The shipper thus acts as a rotation controller to bring about the preponderance either of the reel-advancing action or of the retarding action, thereby to meet the pull, or the slack, created by the variable yarn demand in each cycle. Such arrangement, with constant strong friction on the reel but variable reel drive, Was disclosed in said prior patent; but for the present improvement it is preferable that the resilient pilot or guiderod should act to vary the braking friction on the reel, whether or not a drive means be provided.

The action and yarn motions during each cycle may be further explained and analyzed upon the diagrams Figs. 4 and 6, with Fig. 7 showing a modification to be explained later.

Fig. 4 shows a general diagram of the yarn advance and take-up action as a whole, that is, the entire or resultant motions of the stretch or length of yarn existing at any moment between the knitting point and the yarn guiding system thereabove. Two cycles are shown, one of them being marked with the various salient points of the diagram, lettered a to Z, followed by a etc. for the next cycle. A convenient median or zero line ZZ is taken, for reference purposes. Every second letter, I), d, 1 etc. represents a crossing by the motion curve of th zero line. The remaining points indicate the peaks or the extremes of the upward and downward motions occurring during the cycle; thus a, e, i and repeat indicate the high points while c, g, k and repeat indicate the low points, representing respectively the maximum conditions of slack or release and of demand or pull of the yarns from the knitting point. As already explained the total curveof Fig. 4 is approximate, and represents merely one selected yarn motion operation, from a warp knitting system presenting yarn pull and slack corresponding With the diagram. The motions there represented might be those of the machine and operation of said prior patent, wherein there is but one shiftable yarn guiderod, resiliently controlled to take care of the full sequence of motions involved in such war knitting.

The above described diagram of Fig. 4 is similar to and upon the same principles as that shown in Fig. 4 of said prior Patent No. 2,397,663; being only one however of a great variety of diagrams and knitting cycles which may be carried out by the machine of the present invention.

This diagram of Fig. 4 clearly shows one extreme and two moderate dips or descents of motion, and two moderate and one extreme ascents or rises of motion, all imposed upon the resilient control of the guiderod. This was found to be undesirable, especially as to the two peaks or extremes of motion, not capable of being emciently handled by the resilient mountings of the guiderod, and the resulting extreme compressions and expansions of the tension spring 34 tending to introduce an undesirable lack of uniformity of the tension to be maintained upon the sheet of flowing yarns; drawbacks which have been overcome by the principles of the present invention.

Passing now to the more complete diagram of Fig. 6, this shows how, employing the present invention, the total yarn motions, with three descents and three ascents in each cycle, will be allocated between the two shiftable guiderods, the first under the same resilient control as in said prior patent and the second under an independ-- ent control such as the positive action of a cam the cam I 35 in Fig. 5 showing approximately and in principle the character of a power cam, having: three rises and three dips, which is connected and adapted to operate through the second guiderod to deliver motions thereof causing it to assume a substantial portion, or the greater portion, of the upward and downward yarn supply and takeup motions.

In said Fig. 6 diagram, containing the horizontal zero or median line Z-Z and the upright lines separating the cycles, the positive or cam controlled component of motion is shown by the thin line or curve, the resilient controlled component by the dotted line, and the total motion or resultant by the heavy line. This heavy or total curve line extends through the diagram points a to Z, and thence to a for the next cycle, as in Fig. 4. The positive controlled component, representing the effect of the cam I35, assumes a substantial part of each of the six loops of the curve.

Since part of the positive component substantially coincides with the resultant curve, the former can be traced on Fig. 6 as follows. Starting at a, the assumed starting point of each cycle, the positive component extends downwardly through I), where the curve intersects the median line and thence downwardly through the low point 0 by a descent somewhat more than half of the total descent from the zero line to the point 0; thence upwardly through point (1, and around the upper loop at, e, 1, again crossing the zero line at neutral point I and passing around the lower loop I, g, h, the cam being designed to provide these motions, preferably not fully satisfying the curve of demand or pull and slack created by the knitting motions. Beyond point h at the zero line the positive component follows, not the full loop h, i, but the shortened loop h, F, 7'; and beyond it follows the lower loop 7', 7c, Z, crossing the zero line at Z and ascending to the peak a, thus completing the cycle, the continuing motion to be a repetition for the succeeding cycle.

Coming to the resilient component of the curve and yarn motion, this might take a substantial share of the duty represented by all of the six loops or rises and dips of motion, but it is preferred to let the major part thereof be assumed by the positive control of the cam I 35. Thus, Fig. 6 shows that the resilient part of the motion departs only slightly from the zero line, excepting in the extreme lower loop between b and d and the extreme upper loop between h and i. Approaching the point I) the resilient curve, passing rightward substantially at, but slightly above the zero line, passes smoothly through the point b and then loops downwardly through the lower point or peak 0' and returns upwardly through the point d at the zero level. At this phase of the cycle therefore the resiliently controlled guiderod has been relieved of the major portion of the extreme dip b, c, d, thus relieving the control spring 3 5 of much of its duty, and mini mixing undesirable variations of tension. Beyond the point d the resilient component curve extends along slightly above the zero line, as the control spring retracts the guiderod during the slackening of the yarn demand. Beyond f the resilient component curves downwardly below the Zero line, returning to the point h. These two curve portions d to f and to h represent a resilient motion which is only a small fraction of the total motion atthese parts of the diagram, as almost wholly provided for by the contour of the positive cam. The resilient component passing rightwardly and upwardly. through the point It continues as a high loop h, i, a, preferably somewhat shorter than the loopv 71., i 7' produced by the positive cam. Therebeyond the resilient component curves downwardly again belowthe zero line to a slight extent and thence upwardly through point? and rightwardly above the zero line toward a repetition of cycle.

It will be noted that the heavy line or resultant basic curve of yarn motion, throughouteachcycle, consists of the addition of'thetwo component curves. Thus the extensive dip b, 0, dis shown to be the sum of the positive dip. b, d and the residual motion or resilient dip b, c, d; and the same in the inverse sense with. respect to the extreme or high rise It, i, a" of the basic curve and the two components into which it is subdivided.

As already pointed-out, the contour of the cam I35, or similar power actuated controller, is such as to deliver to the descending yarn stretch a series of motions corresponding to thecomponent of the Fig. 6 diagram extending through a, 0 e, g, 2' and 7c in each cycle, the designing of the cam to be with allowance for any factors introduoed by the character of the-connecting mocha-- ism from the cam to the guiderod lit, thus to deliver to the yarn passing around said guiderod the predetermined supplying and taking up actions thereof. The operation represented by the Fig. 6 diagram is advantageous in that there are noextremely high or low movements of either guiderod required, and the com or device which actuates the second guiderod will have no extremely high or low points, a mechanical advantage.

In certainof these respects the diagram of Fig. '7 is less desirable. ihe '7 diagram is in general like that of Fig. 6, but substantially the total rise at the loop h, i, y is in Fig. 'i assumed by the positive component and cam, retracting upward l "the second guiderod its nearly to the fulli apex of said loop. The resilient component departs only slightly from zero line between It and 7', having only to take care of the residue of the rising motion after the cam actuationv of thesecend guiderod has taken care of slightly less than the entire motion, up to the apex i.

The diagrams of Figs. 6 and 'Z are alike in that between the points 79 and d the-descending motion or loop is divided between the two systems, positive and resilient, so that a very substantial part thereof, of the order of one-half thereof, has to be cared for by the resilient mechanism. This results in both cases in the first guiderod act. and the rockarms which carry it swinging advancingly, upwardly in Figs. 1, 2 and 5, with corresponding supplying of yarn and compression of the spring Thus provided extent oradvancing swing of the tensionrod ample to insure the operation of the shipper i129 andthe relaxar tion of the reel brake action, thus to facilitate the advancing rotation of the reel; for example under the pull of the yarns. Thus, at the time of peak demand the brake is relaxed and the reel rotates slightly to afford the needed extra yarn at this critical point in each cycle of operation. At the same time the desired tension on the yarns ismaintained throughout each cycle, the control spring 36 being constantly in opera tion exerting a-suiiiciently even or steady tension pullupon the yarns owing to the elimination from 14' the spring contriolled component. of yarn motion of any extreme compressions or expansions 'of the spring such as could unduly vary the degree of operative tension during the performing of each knitting cycle.

As already stated, the cam 535 shown in Fig. 5, whose outline has three rises and three clips from the zero circle or line Z, corresponds with the positive component curve of Fig. 6, passing through the six apexes a, c 2, g, i and is. To produce the different action of Fig. 7 with the positive curve rising to the apex i instead of only toi it is only necessary to modify the cam shown in Fig. '5 by increasing the height of its rise i to' the point as shown in dotted lines, leaving all other factors the same. By reason of the resilient control of the guiderod let it takes care of all of the residue of the required total or resultant yarnadvance and take up, consisting mainly of the dip to 0, during which it operates the shipper. to aid in the necessary yarn supply by reel rotation.

Various other cam forms may be used to predetermine the positive component according to the desired motions of the two guiderods; as for example the cam 36 in Fig. 8, wherein are two extended dwells between. a single rise and a single dip, the result of which is that the positive curve will not depart substantially from the Zero line excepting only at the loop which descends to the point c and at the loop rising to i while the lesser rising loops at a and e and dipping loops at hand 7c represent motions all imposed upon the resilient or spring-controlled action of the first guiderod We; the latter thereby being in continuous action but still relieved of the excess shifting actions to the points 0 and 2 which would be incurred'were'there no independently controlled second shiitable guiderod HE.

A- further available modification is one based ont'he modification of 6 of prior Patent No. 2,394,161, descrihable as follows as applied herein. Thedrawings show only a single resiliently controlled guiderod and a single positively controlled rod, in each case the rod being swingable bodily upon a pair of supporting arms rocking on an axle; Instead, either such arm-supported single rod (or both of them) could be replaced by an arm-supported double rod, for example, the arms each becoming a centrally fulcrummed lever, witha front arm for a front rod' and a rear arm for a rear rod, the entirety rocking about the fulchum, andthe yarn passing in succession around both rods; which gives an increased control effect, or else reduces the necessary throw, for a given supplying or taking up of yarn in each cycle, asexplainedrin the prior patent.

Inall cases, with the useof the independently controlled. two guiderods, the resilient action of the control of the first or tension rod is adapted to afford the important'iunctions of (1) meeting the residual demand for yarn beyond what is supplied by the positively controlled action, (2) allowing for irregularities in the extent of the yarn demand by reason of theeoility of the spring control to-adapt the action thereto, (3) communnicating the desired and approximately uniform tension to the yarn by the elastic action of the spring controlled parts, and (4) taking part in and bringing about the actual or relative braking and relaxing of: the frictional. retardation of the reel at predetermined. points in' the cycle. The variable demandifor yarnis satisfied by the combination of the two systems of. control, the posi tive andthe resilient, the supply of yarn bythese combined actions satisfying the demand as to the pull created by certain knitting actions while the combined take-up actions satisfy the slack which is created at certain other points in each cycle.

I claim:

1. In a warp-knitting machine of a kind having a rotatable reel from which the yarns are supplied in the form of an advancing sheet to feed the banks of knitting instruments operable through successive cycles, with a frictional brake means operable in each knitting cycle for methodically retarding the reel rotation and comprising a friction shoe bearing upon a surface rotatable with the reel, and with a movable shipper means operably connected to the shoe to impose or relax variably the braking action on the reel; the combination therewith of a plurality of shiftable yarn guide rods around which in sequence the yarn sheet from the reel fiows advancingly toward the knitting point, each rod being advancingly displaceable and retractingly returnable for the supplying and taking up of the yarn; a first one of said rods having resilient control means rendering it displaceable and returnable in each cycle in response to variations of the pull and slack of the yarns flowing around it caused by variations in the knitting demand for yarn; and a second one of said shiftable rods having control means for displacing and returning it independently of such pull and slack of the flowing yarns and comprising a positive Or power actuated mechanism pretimed to supply yarn to and take up yarn from the knitting point in each cycle to a variable extent coordinated with but insuflicient fully to satisfy such pull and slack of the yarns; and said first rod having a mechanical connection to said shipper whereby, to the extent that the yarn pull in any part of the cycle exceeds the supply afforded by the predetermined deficient advance of the second rod, the resilient yield of the first rod operates through said shipper to relax the braking of the reel thereby to facilitate the rotation of the reel for the feeding of yarn toward the knitting point at that part of the cycle; whereas, to the extent that the slack in any part of the cycle exceeds the takeup afforded by the predetermined deficient retraction of the second rod, the resilient yield of the first rod operates through said shipper to impose the braking of the reel thereby to retard the rotation of the reel for the curtailing of feed of yarn toward the knitting point at that part of the cycle.

2. In a warp-knitting machine of a kind having a rotatable reel from which the warp yarns are supplied in the form of an. advancing sheet to feed the banks of knitting instruments operable for knitting through successive cycles, with a frictional rotation-restrainingg means operable in each knitting cycle for retarding the reel rotation, and a variable rotation-promoting means, which may include the knitting mechanism acting through the variable pull of the supplied yarns, tending to advance the reel rotatively in each cycle; the combination with said restraining and promoting means of a shiftable reelrotation controller or shipper adapted when shifted to cause the relative operation of said restraining and said promoting means to deliver a preponderance of retarding or of advancing eifect upon the reel, a plurality of shiftable yarn guiderods around which in sequence the yarn sheet from the reel flows advancingly toward the knitting point, each rod being advancingly displaceable and retractingly returnable for the supplying and taking up respectively of the yarn; a first one of said rods having resilient control means rendering said rod displaceable and returnable in each cycle in response to variations of the pull and slack of the yarns flowing around it caused by variations in the knitting demand for yarn, and said resilient means adapted to impose a continuous tension upon such yarn; and a second one of said shiftable rods having a separate control means for displacing and returning it comprising a positive or power actuated mechanism pretirned to supply yarn to and take up yarn from the knitting point in each cycle to a variable extent coordinated with but insufiicient to satisfy such pull and slack of the yarns; and said first rod having a mechanical connection to said rotation controller whereby, to the extent that the variable yarn demand in any part of the cycle exceeds the supply afforded by the aforesaid predetermined deficient advance of the second rod, the resilient yield of the first rod operates through said rotation controller to bring about a preponderance of the reel-advancing action thereby to meet the unsatisfied residue of the variable yarn demand in each cycle.

3. In a warp-knitting machine having a reel to supply yarns to the knitting instruments, and a brake operable in each cycle to apply friction variably to a surface rotating with the reel, the combination therewith of at least two shiftably mounted yarn guiderods around each of which the supplied yarns fiow toward the knitting point and each of which is shiftably advanceable and retractable for supplying and taking up the yarns; a first or tension rod having spring control means tending to retract it and being thereby resiliently responsive to variations of yarn pull and slack due to the knitting actions in each cycle; a second or supplemental rod having positive control or cam means for advancing and retracting it pretimed to supply and take up yarn in each cycle to a variable extent coordinated partly but not fully with such pull and slack; and the first rod having an operative connection to said reel brake such that, to the extent that the yarn pull at a high-demand cycle point exceeds the supply afforded by the pretimed advance of the second rod, the spring yield of the first rod operates to relax the braking of the reel and thus aid the rotation of the reel for the feeding of yarn toward the knitting point.

4. In a warp-knitting machine having a reel to supply yarns to the knitting instruments, and a brake operable in each cycle to apply friction variably to a surface rotating with the reel, the combination therewith of two yarn guiderods around which in tandem the supplied yarns flow toward the knitting point, each of which rods is shiftably advanceable and retractable for supplying and taking up the yarns; one of said rods being a tension rod having spring control means tending to retract it and being thereby resiliently yieldable and responsive to variations of yarn pull and. slack due to the varying demands of the knitting actions in each cycle; the second rod having a cam 0r pretimed control means for advancing and retracting it in a predetermined manner to supply and take up yarn in each cycle to a variable extent coordinated partly but not fully with the knitting pull and slack, and the cam timing being such that at a time when the yarn demand or pull is at a peak or maximum the second rod by its advance supplies a substantial portion only of the demand while leaving a substantial; residueonhc oi; the demand tohcflul plied by the yield of; thetension. rodxandc' the: tension rod having. n operative. connection o. said: reel. brake such..that,.to. theextcnt tha the. yarn. pull. atthe peak demand. of the. cycle exceeds.v the supply. afforded-by the. pretimcd.. d vance of the secondrodthe spring. yield of. the tension rod. operates. through. such connection torelaiethe brakingof the-reel. thus; td cooperate; in. the. rotation of. thereel for. the feeding of; yarn from the reel toward the knittin h 5. In awarp-knitting. machine. having a, reel that isrotatable to:.supply yarns to the, knittin instruments in..each knitting. cycle thecombina; tion. therewith. of two; separate. but comp1cmcn-- tary yarn guiderods aroundwhicbi. in sequence; the supplied yarns.flowtowardtheknitting point, each of which. rodsis. shiitably advanceable and: retractable forv supplying and. taking up the. yarns;. the. first. of said rods. being. a; tensionsrod having resilient controlmeans tending. to retract the.- rod and being thercby:.yie1dably responsive tot-variationsv of. yarn pulL and. slack due: to the. varying demands .01theknittinaactions in each: cycle; the .s.econd:rod having. a. pr timed cam controlmeansof relatively positive. ch r ct r. for ad.- vancing and. retracting it in a predetermined manner tdsupply; and take up yarn ineach cyclet avariablekextent coordinated partly but not.

fully with such knitting pulland slack and the cam timingbeing such thatat least at that point of; time in the cyclewhen the yarn demand is at a peakthe second rod by its advance supplies a substantial portion only of the. demand while leaving a substantial residue only of. thedemand to be supplied by the. yield of the tension rod; thereby causing the tension rod andits resilient control means to berelieved of the extremes of action to which. they would be subjected in the, absence of such a complementary positive rod; whereby the tensioning of the yarns is rendered more nearly uniform .or steady.

6. The. method of operating. a, warp-knitting machine. of. a kind. having. a reel advancingly rotatable to feed a sheet of yarns toward the. knitting instruments, and a brake, to apply vari'- able friction to retardthe.reeli in each, cycle, and two shiftable yarn guid'crods arran'gedi'n sequence; between thereeland" the knitting point each advan'ceabie 'andiret'ractable to supply andtake up the yarns; said method'comprising resilientlyurging the first-rodretractingly'in' opposition tothe pull'of the yarns whereby said rod shifts responsively to the variable yarn" demand through-- out" each cycle, while advancingandretracting-- thesecond" rod in a predetermined manner to. supply yarn coordinated partially with the pull and slack caused by the demand of the knittingac't-ions thereby leaving a residue of demandtd be supplied by the resilientyieldof the first rod,

which thereby applies continuous tension to the yarns without excess tension; and causing said...

18.- the; first-10f" said rodszbeinga atensionsrodhayinz; resilient control: means tending to. retract. the;v rod and being. thereby yieldably responsiveto; variations ofv yarnipullandsslachdue tothevarh ing demands ofrtheknitting actionsin. eachcyclc the secondrod: having; a pretimed. control. me ns for advancing and retracting it: to; supply. and.

take up. yarn in each; cycleto; a. predetermined extent? coordinated. generally but. notiully with; thevariations of Such knitting. pull. andslac);;.. and: the timing of said. pretimed: controlmcainfir being. such that. at that. part or; the. cyclewhcrcizb the yarn demand is at its maximum the second, rod byits. advance; supplies. a. substantialportion only of the; demand while leaving: a. sub? stantial=- residue only. of thedemand; to he..- slm plied: by. the; yield: of: the .tension. rod; causing the resilienticontrol. means: of; the: first rodto he. relievedof. extremes of actionwherebp the tensioningiof the; yarns is. rendered; more. nearly even or steady. during-each cycle.

8. A warp-knitting machine of a kindhaying; a reel. advancingly. rotatable; to. feed av sheet, 01 yarn toward the. knitting. instruments, and, a; brake. to apply variable iriction to. retard. the. reel; in each cycle; andin combination. therewithltwog. shiftableyarnguiderods arranged in sequence-be tween the reel and; knitting point. each. advance?- ableand: retractablelto supplyand take; up the yarns; together with.meansi.for resiliently: urg ing the first rod. retractingly in opposition, to the knitting pull of: theyarns. whereby saidlmd; shifts responsively to. the variableyarn dcmande throughouteach cycle,.means.for advancing and; retracting the second. rod. in: a predetermined; manner to supply. yarncoordinated partially; with. the pull and slack caused by. the. demandof he; knitting actionsthereby. to leave. a residue... Oi demand to be. supplied bythe; resilient yield. 0i: the firstrod, and. whereby the first rodtherebx applies. continuousstension to the. yarns withollir excess tension; and connecting means for caus ing said first rod,- by its. partialshiftins yield-t0 the yarn pullat peakidemanidito' relax there? tarding friction. of said' brakeandtherebr fac l tate the advancing. rotation. of; the ..ee1i to feed.- yarn towardthe knittingjnstrumcnts...

9'. In a warp-knitting machine having a ree rotatable to supply. asheet of yarn to the knitting. instruments, and; a brake; ans Operable in. each cycle to.-. maintain friction upon a sur face rotating. with. the reel to retard normally theireel the combination therewith of cooperative guiderods. around which in, sequence thesupplied yarn sheet. flows tow he knitt nhv point and each ofiwhich'. node. is shiftab-ly ad, vanceable and retractable for supplying and tal ins up. respectively the; yarns;v the first of said, rods. beingtatensicn; d, having a resilient control means or spring, endi g. to. retract it and being thereby .yieldinsly' responsive to variations. of yarn pull. and slack due to the varying de mands of thcgknittingactions in each-cycle; the. second rod having; a. pretimed control means or, cam for advancing and retracting it in a pre-.-

determined way to suplily and take upyarnirr.

each cycle in. such, manner. that at that part of, the cycle wherein the yarn demand is maximum the; second rod by its advance supplies a sub-1 stantial. portion only of the demandwhile leav ing; a substantial residue only of the demand to: be supplied by-theresilient yield oi the first rod; and the first. or. tensionrod having an. Operative. connection to said reel brake such that, to the.- extent that the yarn. pull at the cycle part. of

l9 maximum demand exceeds the supply afforded by the pretimed advance of the second rod, the resulting resilient yield of the first rod operates through saidconnection to. relax the braking of the reel thus to facilitate the rotation of the reel as required for the feeding of extra yarn toward the knitting point.

10; A warp knitting machine as in claim 7 and wherein the first and second yarn sheet guiderods have rockarms upon which they are swingingly carried and said rockarms for both rods are fulcrummed to swing about a common axle.

--11. A warp knitting machine as in claim 7 and wherein the first and second yarn sheet guiderods have rockarms upon which they are swingingly carried and said rockarms for both rods are fulcrummed to swing about a common axle; the first rod arms extending inwardly from and being fast upon said axle as a rockshaft, and the second rod arms being loose and extending outwardly.

'12. A warp knitting machine as in claim 7 and wherein the second yarn rod has rockarms by which it is swingingly mounted for its advancing and retracting shifts in each cycle, and is provided with a pretimed actuating means and with connections therefrom to the rockarms.

13. A warp knitting machine as in claim '7 and wherein the second yarn rod has rockarms [by which it is swingingly mounted for its advancing and retracting shifts in each cycle, and is provided with a pretimed actuating means and with connections therefrom to the rockarms; said actuating means comprising a special device or cam having power means to rotate it continuously and formed with a structure or contour coordinated with the varying yarn demand of the knitting action in each cycle, and mechanical connections from said device or cam to said second yarn rod to shift the latter correspondingly.

"14. In a warp-knitting machine having a yarn reel that is rotatable to supply a sheet of yarns to the knitting instruments, and a brake means operable in each cycle to apply friction upon a surface rotating in unison with the reel to retard normally the advance of the reel, the combination therewith of two independent but cooperative guiderods around which in sequence the supplied yarn sheet flows advancingly toward the knitting point and each of which rods is shiftably advanceable and retractable for supplying and taking up respectively the yarns; said guide rods having rockarms on which they are swin ingly carried and said rockarms being fulcrummed to swing about a common axle; the first of said rods being a yarn tensioning rod having a control spring tending resiliently to retract said rod and being thereby yieldingly responsive to variations of yarn pull and slack due to the varying demands of the knitting actions in each cycle; the second rod having a pretimed control cam for advancing and retracting it in a predetermined way to supply and take up yarn in each cycle in such manner that at that part of the cycle wherein the yarn demand is maximum thesecond rod by its advance shift supplies a substantial portion only of the demand while leaving a substantial residue only of the demand to be supplied by the resilient yield of the first rod; and the first or tension rod having an operative connection to said reel brake means such that, to the extent that the yarn pull at the cycle part of maximum demand exceeds the supply afforded by the pretimed advance of the second rod, the resulting resilient yield of the first rod operates through said connection to relax the friction [braking of the reel, thereby to facilitate the rotation of the reel at such part of the cycle as required for the feeding of extra yarn toward the knitting point.

15. A warp knitting machine as in claim 14 and wherein said common axle is a rockshaft, and the arms carrying the first yarn rod are fast on said rockshaft, and the arms carrying the second rod are loose on said rockshaft.

16. A warp knitting machine as in claim 15 and wherein the first rod arms and the second rod arms extend respectively substantially oppositely from said rockshaft.

17. A warp knitting machine as in claim 16 and wherein the first rod arms extend inwardly from the rockshaft upon which they are fast, the second rod arms being loose thereon and extending outwardly thereon.

18. In a warp-knitting machine having a yarn reel that is rotatable to supply a sheet of yarns to the knitting instruments, and a brake means operable in each cycle to apply friction upon a.

surface rotating in unison with the reel to retard normall the advance of the reel, the combination therewith of two independent but 00- operative guiderods around which in sequence the supplied yarn sheet flows advancingly toward the knitting point and each of which rods is shiftably advanceable and retractable for supplying and taking up respectively the yarns; the first of said rods being a yarn tensioning rod having a control spring tending resiliently to retract said rod and being thereby yieldingly responsive to variations of yarn pull and slack due to the varying demands of the knitting actions in each cycle; the second rod being swingably mounted by rockarms for its advancing and retracting cyclical shifts and having pretimed actuating means and connections to said rockarms for advanci and retracting the second rod in a predetermined wa to supply and take up yarn in each cycle in such manner that at that part of the cycle wherein the yarn demand is maximum the second rod by its advance shift supplies a substantial portionvonly of the demand while leaving a substantial residue only of the demand to be supplied by the resilient yield of the first rod; and the first or tension rod having an operative connection to said reel brake means such that, to the extent that the yarn pull at the cycle part of maximum demand exceeds the supply afiorded by the pretimed advance of the second rod, the resulting resilient yield of the first rod operates through said connection to relax the friction braking of the reel, thereby to facilitate the rotaknitting point.

19. A warp knitting machine as in claim 18 and wherein said actuating means to the second guiderod comprises a pre-existing rocker or swinging bracket taking part in the knitting actions, and linkage from said rocker to the rockarms of the second rod to actuate the latter.

20. A warp knitting machine as in claim 18 and wherein said actuating means for the second guiderod comprises an actuating cam having power means to drive it continuously, and formed with an operative contour coordinated with the varying yarn demand of the knitting action in each cycle, and having mechanical connections 21 from said cam to said second rod to shift the latter correspondingly.

21. In a warp knitting machine of the kind described wherein the yarns in advancing from the supply reel to the knitting point are maintained under controlled variable tension through knitting cycle after cycle, a yarn tension control means comprising separate but cooperatively shiftable yarn guide rods disposed parallel to the reel and over which in succession the yarns travel toward the knitting point; one of said guide rods having for efiecting its actuation a cyclically driven cam means of predetermined cam formation and with predetermined yarn tension control action during each cycle; and another of said guide rods having for effecting its shifting actions in cooperation with the pull of the yarns a resiliently yieldable mounting means providing for the guide rod and yarns a predetermined floating tension control action during each cycle; and wherein the reel has means for varying the retarding action applied to its rotation; and wherein the second mentioned guide rod, shift- 22 able under its predetermined floating tension mounting, has means connecting it to said reel retardation means, thereby to restrain undue yarn feed at a predetermined part of each cycle.

CARLOS A. I-lEPP.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,014,530 Kinsell-a et a1. Sept. 17, 1935 2,394,161 Fiorentino Feb. 5, 1946 2,397,663 Hepp Apr. 2, 1946 2,430,022 Lambach Nov. 4, 1947 2,441,189 Eshleman May 11, 1948 2,451,499 Lambach Oct. 19, 1948 FOREIGN PATENTS 20 Number Country Date 554,806 Germany July 12, 1932 555,678 France Mar. 28, 1923 

